lib/set-permissions.c

/* Set permissions of a file.  -*- coding: utf-8 -*-

   Copyright (C) 2002-2003, 2005-2026 Free Software Foundation, Inc.

   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <https://www.gnu.org/licenses/>.

   Written by Paul Eggert, Andreas Grünbacher, and Bruno Haible.  */

#include <config.h>

#include "acl.h"

#include "acl-internal.h"
#include "minmax.h"

#if USE_ACL
# if ! defined HAVE_ACL_FROM_MODE && defined HAVE_ACL_FROM_TEXT /* FreeBSD, Cygwin >= 2.5 */
#  if HAVE_ACL_GET_FILE && !HAVE_ACL_TYPE_EXTENDED

static acl_t
acl_from_mode (mode_t mode)
{
  char acl_text[] = "u::---,g::---,o::---";

  if (mode & S_IRUSR) acl_text[ 3] = 'r';
  if (mode & S_IWUSR) acl_text[ 4] = 'w';
  if (mode & S_IXUSR) acl_text[ 5] = 'x';
  if (mode & S_IRGRP) acl_text[10] = 'r';
  if (mode & S_IWGRP) acl_text[11] = 'w';
  if (mode & S_IXGRP) acl_text[12] = 'x';
  if (mode & S_IROTH) acl_text[17] = 'r';
  if (mode & S_IWOTH) acl_text[18] = 'w';
  if (mode & S_IXOTH) acl_text[19] = 'x';

  return acl_from_text (acl_text);
}
#  endif
# endif

# if HAVE_FACL && defined GETACL /* Solaris, Cygwin < 2.5, not HP-UX */
static int
set_acls_from_mode (const char *name, int desc, mode_t mode, bool *must_chmod)
{
#  ifdef ACE_GETACL
  /* Solaris also has a different variant of ACLs, used in ZFS and NFSv4
     file systems (whereas the other ones are used in UFS file systems).  */

  /* The flags in the ace_t structure changed in a binary incompatible way
     when ACL_NO_TRIVIAL etc. were introduced in <sys/acl.h> version 1.15.
     How to distinguish the two conventions at runtime?
     We fetch the existing ACL.  In the old convention, usually three ACEs have
     a_flags = ACE_OWNER / ACE_GROUP / ACE_OTHER, in the range 0x0100..0x0400.
     In the new convention, these values are not used.  */
  int convention;

  {
    /* Initially, try to read the entries into a stack-allocated buffer.
       Use malloc if it does not fit.  */
    enum
      {
        alloc_init = 4000 / sizeof (ace_t), /* >= 3 */
        alloc_max = MIN (INT_MAX, SIZE_MAX / sizeof (ace_t))
      };
    ace_t buf[alloc_init];
    size_t alloc = alloc_init;
    ace_t *entries = buf;
    ace_t *malloced = NULL;
    int count;

    for (;;)
      {
        count = (desc != -1
                 ? facl (desc, ACE_GETACL, alloc, entries)
                 : acl (name, ACE_GETACL, alloc, entries));
        if (count < 0 && errno == ENOSPC)
          {
            /* Increase the size of the buffer.  */
            free (malloced);
            if (alloc > alloc_max / 2)
              {
                errno = ENOMEM;
                return -1;
              }
            alloc = 2 * alloc; /* <= alloc_max */
            entries = malloced = (ace_t *) malloc (alloc * sizeof (ace_t));
            if (entries == NULL)
              {
                errno = ENOMEM;
                return -1;
              }
          }
        else
          break;
      }

    if (count <= 0)
      convention = -1;
    else
      {
        convention = 0;
        for (int i = 0; i < count; i++)
          if (entries[i].a_flags & (OLD_ACE_OWNER | OLD_ACE_GROUP | OLD_ACE_OTHER))
            {
              convention = 1;
              break;
            }
      }
    free (malloced);
  }

  if (convention >= 0)
    {
      ace_t entries[6];
      int count;

      if (convention)
        {
          /* Running on Solaris 10.  */
          entries[0].a_type = OLD_ALLOW;
          entries[0].a_flags = OLD_ACE_OWNER;
          entries[0].a_who = 0; /* irrelevant */
          entries[0].a_access_mask = (mode >> 6) & 7;
          entries[1].a_type = OLD_ALLOW;
          entries[1].a_flags = OLD_ACE_GROUP;
          entries[1].a_who = 0; /* irrelevant */
          entries[1].a_access_mask = (mode >> 3) & 7;
          entries[2].a_type = OLD_ALLOW;
          entries[2].a_flags = OLD_ACE_OTHER;
          entries[2].a_who = 0;
          entries[2].a_access_mask = mode & 7;
          count = 3;
        }
      else
        {
          /* Running on Solaris 10 (newer version) or Solaris 11.
             The details here were found through "/bin/ls -lvd somefiles".  */
          entries[0].a_type = NEW_ACE_ACCESS_DENIED_ACE_TYPE;
          entries[0].a_flags = NEW_ACE_OWNER;
          entries[0].a_who = 0; /* irrelevant */
          entries[0].a_access_mask = 0;
          entries[1].a_type = NEW_ACE_ACCESS_ALLOWED_ACE_TYPE;
          entries[1].a_flags = NEW_ACE_OWNER;
          entries[1].a_who = 0; /* irrelevant */
          entries[1].a_access_mask = NEW_ACE_WRITE_NAMED_ATTRS
                                     | NEW_ACE_WRITE_ATTRIBUTES
                                     | NEW_ACE_WRITE_ACL
                                     | NEW_ACE_WRITE_OWNER;
          if (mode & 0400)
            entries[1].a_access_mask |= NEW_ACE_READ_DATA;
          else
            entries[0].a_access_mask |= NEW_ACE_READ_DATA;
          if (mode & 0200)
            entries[1].a_access_mask |= NEW_ACE_WRITE_DATA | NEW_ACE_APPEND_DATA;
          else
            entries[0].a_access_mask |= NEW_ACE_WRITE_DATA | NEW_ACE_APPEND_DATA;
          if (mode & 0100)
            entries[1].a_access_mask |= NEW_ACE_EXECUTE;
          else
            entries[0].a_access_mask |= NEW_ACE_EXECUTE;
          entries[2].a_type = NEW_ACE_ACCESS_DENIED_ACE_TYPE;
          entries[2].a_flags = NEW_ACE_GROUP | NEW_ACE_IDENTIFIER_GROUP;
          entries[2].a_who = 0; /* irrelevant */
          entries[2].a_access_mask = 0;
          entries[3].a_type = NEW_ACE_ACCESS_ALLOWED_ACE_TYPE;
          entries[3].a_flags = NEW_ACE_GROUP | NEW_ACE_IDENTIFIER_GROUP;
          entries[3].a_who = 0; /* irrelevant */
          entries[3].a_access_mask = 0;
          if (mode & 0040)
            entries[3].a_access_mask |= NEW_ACE_READ_DATA;
          else
            entries[2].a_access_mask |= NEW_ACE_READ_DATA;
          if (mode & 0020)
            entries[3].a_access_mask |= NEW_ACE_WRITE_DATA | NEW_ACE_APPEND_DATA;
          else
            entries[2].a_access_mask |= NEW_ACE_WRITE_DATA | NEW_ACE_APPEND_DATA;
          if (mode & 0010)
            entries[3].a_access_mask |= NEW_ACE_EXECUTE;
          else
            entries[2].a_access_mask |= NEW_ACE_EXECUTE;
          entries[4].a_type = NEW_ACE_ACCESS_DENIED_ACE_TYPE;
          entries[4].a_flags = NEW_ACE_EVERYONE;
          entries[4].a_who = 0;
          entries[4].a_access_mask = NEW_ACE_WRITE_NAMED_ATTRS
                                     | NEW_ACE_WRITE_ATTRIBUTES
                                     | NEW_ACE_WRITE_ACL
                                     | NEW_ACE_WRITE_OWNER;
          entries[5].a_type = NEW_ACE_ACCESS_ALLOWED_ACE_TYPE;
          entries[5].a_flags = NEW_ACE_EVERYONE;
          entries[5].a_who = 0;
          entries[5].a_access_mask = NEW_ACE_READ_NAMED_ATTRS
                                     | NEW_ACE_READ_ATTRIBUTES
                                     | NEW_ACE_READ_ACL
                                     | NEW_ACE_SYNCHRONIZE;
          if (mode & 0004)
            entries[5].a_access_mask |= NEW_ACE_READ_DATA;
          else
            entries[4].a_access_mask |= NEW_ACE_READ_DATA;
          if (mode & 0002)
            entries[5].a_access_mask |= NEW_ACE_WRITE_DATA | NEW_ACE_APPEND_DATA;
          else
            entries[4].a_access_mask |= NEW_ACE_WRITE_DATA | NEW_ACE_APPEND_DATA;
          if (mode & 0001)
            entries[5].a_access_mask |= NEW_ACE_EXECUTE;
          else
            entries[4].a_access_mask |= NEW_ACE_EXECUTE;
          count = 6;
        }

      int ret;
      if (desc != -1)
        ret = facl (desc, ACE_SETACL, count, entries);
      else
        ret = acl (name, ACE_SETACL, count, entries);
      if (ret < 0 && errno != EINVAL && errno != ENOTSUP)
        {
          if (errno == ENOSYS)
            {
              *must_chmod = true;
              return 0;
            }
          return -1;
        }
      if (ret == 0)
        return 0;
    }
#  endif

  {
    aclent_t entries[3];

    entries[0].a_type = USER_OBJ;
    entries[0].a_id = 0; /* irrelevant */
    entries[0].a_perm = (mode >> 6) & 7;
    entries[1].a_type = GROUP_OBJ;
    entries[1].a_id = 0; /* irrelevant */
    entries[1].a_perm = (mode >> 3) & 7;
    entries[2].a_type = OTHER_OBJ;
    entries[2].a_id = 0;
    entries[2].a_perm = mode & 7;

    int ret;
    if (desc != -1)
      ret = facl (desc, SETACL,
                  sizeof (entries) / sizeof (aclent_t), entries);
    else
      ret = acl (name, SETACL,
                 sizeof (entries) / sizeof (aclent_t), entries);
    if (ret < 0)
      {
        if (errno == ENOSYS || errno == EOPNOTSUPP)
          {
            *must_chmod = true;
            return 0;
          }
        return -1;
      }
    return 0;
  }
}

# elif HAVE_GETACL /* HP-UX */
static int
context_acl_from_mode (struct permission_context *ctx, const char *name, int desc)
{
  struct stat statbuf;

  int ret;
  if (desc != -1)
    ret = fstat (desc, &statbuf);
  else
    ret = stat (name, &statbuf);
  if (ret < 0)
    return -1;

  ctx->entries[0].uid = statbuf.st_uid;
  ctx->entries[0].gid = ACL_NSGROUP;
  ctx->entries[0].mode = (ctx->mode >> 6) & 7;
  ctx->entries[1].uid = ACL_NSUSER;
  ctx->entries[1].gid = statbuf.st_gid;
  ctx->entries[1].mode = (ctx->mode >> 3) & 7;
  ctx->entries[2].uid = ACL_NSUSER;
  ctx->entries[2].gid = ACL_NSGROUP;
  ctx->entries[2].mode = ctx->mode & 7;
  ctx->count = 3;
  return 0;
}

#  if HAVE_ACLV_H /* HP-UX >= 11.11 */
static int
context_aclv_from_mode (struct permission_context *ctx)
{
  ctx->aclv_entries[0].a_type = USER_OBJ;
  ctx->aclv_entries[0].a_id = 0; /* irrelevant */
  ctx->aclv_entries[0].a_perm = (ctx->mode >> 6) & 7;
  ctx->aclv_entries[1].a_type = GROUP_OBJ;
  ctx->aclv_entries[1].a_id = 0; /* irrelevant */
  ctx->aclv_entries[1].a_perm = (ctx->mode >> 3) & 7;
  ctx->aclv_entries[2].a_type = CLASS_OBJ;
  ctx->aclv_entries[2].a_id = 0;
  ctx->aclv_entries[2].a_perm = (ctx->mode >> 3) & 7;
  ctx->aclv_entries[3].a_type = OTHER_OBJ;
  ctx->aclv_entries[3].a_id = 0;
  ctx->aclv_entries[3].a_perm = ctx->mode & 7;
  ctx->aclv_count = 4;

  int ret = aclsort (ctx->aclv_count, 1, ctx->aclv_entries);
  if (ret > 0)
    abort ();
  return ret;
}
#  endif

# elif HAVE_ACLX_GET && defined ACL_AIX_WIP /* AIX */
static int
set_acls_from_mode (const char *name, int desc, mode_t mode, bool *must_chmod)
{
  acl_type_list_t types;
  size_t types_size = sizeof (types);

  if (aclx_gettypes (name, &types, &types_size) < 0
      || types.num_entries == 0)
    {
      *must_chmod = true;
      return 0;
    }

  /* XXX Do we need to clear all types of ACLs for the given file, or is it
     sufficient to clear the first one?  */
  acl_type_t type = types.entries[0];
  if (type.u64 == ACL_AIXC)
    {
      union { struct acl a; char room[128]; } u;

      u.a.acl_len = (char *) &u.a.acl_ext[0] - (char *) &u.a; /* no entries */
      u.a.acl_mode = mode & ~(S_IXACL | 0777);
      u.a.u_access = (mode >> 6) & 7;
      u.a.g_access = (mode >> 3) & 7;
      u.a.o_access = mode & 7;

      int ret;
      if (desc != -1)
        ret = aclx_fput (desc, SET_ACL | SET_MODE_S_BITS,
                         type, &u.a, u.a.acl_len, mode);
      else
        ret = aclx_put (name, SET_ACL | SET_MODE_S_BITS,
                        type, &u.a, u.a.acl_len, mode);
      if (!(ret < 0 && errno == ENOSYS))
        return ret;
    }
  else if (type.u64 == ACL_NFS4)
    {
      union { nfs4_acl_int_t a; char room[128]; } u;
      u.a.aclVersion = NFS4_ACL_INT_STRUCT_VERSION;
      u.a.aclEntryN = 0;

      nfs4_ace_int_t *ace = &u.a.aclEntry[0];
      {
        ace->flags = ACE4_ID_SPECIAL;
        ace->aceWho.special_whoid = ACE4_WHO_OWNER;
        ace->aceType = ACE4_ACCESS_ALLOWED_ACE_TYPE;
        ace->aceFlags = 0;
        ace->aceMask =
          (mode & 0400 ? ACE4_READ_DATA | ACE4_LIST_DIRECTORY : 0)
          | (mode & 0200
             ? ACE4_WRITE_DATA | ACE4_ADD_FILE | ACE4_APPEND_DATA
               | ACE4_ADD_SUBDIRECTORY
             : 0)
          | (mode & 0100 ? ACE4_EXECUTE : 0);
        ace->aceWhoString[0] = '\0';
        ace->entryLen = (char *) &ace->aceWhoString[4] - (char *) ace;
        ace = (nfs4_ace_int_t *) (char *) &ace->aceWhoString[4];
        u.a.aclEntryN++;
      }
      {
        ace->flags = ACE4_ID_SPECIAL;
        ace->aceWho.special_whoid = ACE4_WHO_GROUP;
        ace->aceType = ACE4_ACCESS_ALLOWED_ACE_TYPE;
        ace->aceFlags = 0;
        ace->aceMask =
          (mode & 0040 ? ACE4_READ_DATA | ACE4_LIST_DIRECTORY : 0)
          | (mode & 0020
             ? ACE4_WRITE_DATA | ACE4_ADD_FILE | ACE4_APPEND_DATA
               | ACE4_ADD_SUBDIRECTORY
             : 0)
          | (mode & 0010 ? ACE4_EXECUTE : 0);
        ace->aceWhoString[0] = '\0';
        ace->entryLen = (char *) &ace->aceWhoString[4] - (char *) ace;
        ace = (nfs4_ace_int_t *) (char *) &ace->aceWhoString[4];
        u.a.aclEntryN++;
      }
      {
        ace->flags = ACE4_ID_SPECIAL;
        ace->aceWho.special_whoid = ACE4_WHO_EVERYONE;
        ace->aceType = ACE4_ACCESS_ALLOWED_ACE_TYPE;
        ace->aceFlags = 0;
        ace->aceMask =
          (mode & 0004 ? ACE4_READ_DATA | ACE4_LIST_DIRECTORY : 0)
          | (mode & 0002
             ? ACE4_WRITE_DATA | ACE4_ADD_FILE | ACE4_APPEND_DATA
               | ACE4_ADD_SUBDIRECTORY
             : 0)
          | (mode & 0001 ? ACE4_EXECUTE : 0);
        ace->aceWhoString[0] = '\0';
        ace->entryLen = (char *) &ace->aceWhoString[4] - (char *) ace;
        ace = (nfs4_ace_int_t *) (char *) &ace->aceWhoString[4];
        u.a.aclEntryN++;
      }
      u.a.aclLength = (char *) ace - (char *) &u.a;

      int ret;
      if (desc != -1)
        ret = aclx_fput (desc, SET_ACL | SET_MODE_S_BITS,
                         type, &u.a, u.a.aclLength, mode);
      else
        ret = aclx_put (name, SET_ACL | SET_MODE_S_BITS,
                        type, &u.a, u.a.aclLength, mode);
      if (!(ret < 0 && errno == ENOSYS))
        return ret;
    }

  *must_chmod = true;
  return 0;
}

# elif HAVE_STATACL /* older AIX */
static int
context_acl_from_mode (struct permission_context *ctx)
{
  ctx->u.a.acl_len = (char *) &ctx->u.a.acl_ext[0] - (char *) &ctx->u.a; /* no entries */
  ctx->u.a.acl_mode = ctx->mode & ~(S_IXACL | 0777);
  ctx->u.a.u_access = (ctx->mode >> 6) & 7;
  ctx->u.a.g_access = (ctx->mode >> 3) & 7;
  ctx->u.a.o_access = ctx->mode & 7;
  ctx->have_u = true;
  return 0;
}

# elif HAVE_ACLSORT /* NonStop Kernel */
static int
context_acl_from_mode (struct permission_context *ctx)
{
  ctx->entries[0].a_type = USER_OBJ;
  ctx->entries[0].a_id = 0; /* irrelevant */
  ctx->entries[0].a_perm = (ctx->mode >> 6) & 7;
  ctx->entries[1].a_type = GROUP_OBJ;
  ctx->entries[1].a_id = 0; /* irrelevant */
  ctx->entries[1].a_perm = (ctx->mode >> 3) & 7;
  ctx->entries[2].a_type = CLASS_OBJ;
  ctx->entries[2].a_id = 0;
  ctx->entries[2].a_perm = (ctx->mode >> 3) & 7;
  ctx->entries[3].a_type = OTHER_OBJ;
  ctx->entries[3].a_id = 0;
  ctx->entries[3].a_perm = ctx->mode & 7;
  ctx->count = 4;

  int ret = aclsort (ctx->count, 1, entries);
  if (ret > 0)
    abort ();
  return ret;
}
# endif

static int
set_acls (struct permission_context *ctx, const char *name, int desc,
          int from_mode, bool *must_chmod, bool *acls_set)
{
  int ret = 0;

# if HAVE_ACL_GET_FILE
  /* POSIX 1003.1e (draft 17 -- abandoned) specific version.  */
  /* Linux, FreeBSD, Mac OS X, Cygwin >= 2.5 */
#  if !HAVE_ACL_TYPE_EXTENDED
  /* Linux, FreeBSD, Cygwin >= 2.5 */

#   ifndef HAVE_ACL_FROM_TEXT
#    error Must have acl_from_text (see POSIX 1003.1e draft 17).
#   endif
#   ifndef HAVE_ACL_DELETE_DEF_FILE
#    error Must have acl_delete_def_file (see POSIX 1003.1e draft 17).
#   endif

  if (! ctx->acls_not_supported)
    {
      if (ret == 0 && from_mode)
        {
          if (ctx->acl)
            acl_free (ctx->acl);
          ctx->acl = acl_from_mode (ctx->mode);
          if (ctx->acl == NULL)
            ret = -1;
        }

      if (ret == 0 && ctx->acl)
        {
          if (HAVE_ACL_SET_FD && desc != -1)
            ret = acl_set_fd (desc, ctx->acl);
          else
            ret = acl_set_file (name, ACL_TYPE_ACCESS, ctx->acl);
          if (ret != 0)
            {
              if (! acl_errno_valid (errno))
                {
                  ctx->acls_not_supported = true;
                  if (from_mode || acl_access_nontrivial (ctx->acl) == 0)
                    ret = 0;
                }
            }
          else
            {
              *acls_set = true;
              if (S_ISDIR(ctx->mode))
                {
                  if (! from_mode && ctx->default_acl &&
                      acl_default_nontrivial (ctx->default_acl))
                    ret = acl_set_file (name, ACL_TYPE_DEFAULT,
                                        ctx->default_acl);
                  else
                    ret = acl_delete_def_file (name);
                }
            }
        }
    }

#   if HAVE_ACL_TYPE_NFS4  /* FreeBSD */

  /* File systems either support POSIX ACLs (for example, ufs) or NFS4 ACLs
     (for example, zfs). */

  /* TODO: Implement setting ACLs once get_permissions() reads them. */

#   endif

#  else /* HAVE_ACL_TYPE_EXTENDED */
  /* Mac OS X */

  /* On Mac OS X,  acl_get_file (name, ACL_TYPE_ACCESS)
     and           acl_get_file (name, ACL_TYPE_DEFAULT)
     always return NULL / EINVAL.  You have to use
                   acl_get_file (name, ACL_TYPE_EXTENDED)
     or            acl_get_fd (open (name, ...))
     to retrieve an ACL.
     On the other hand,
                   acl_set_file (name, ACL_TYPE_ACCESS, acl)
     and           acl_set_file (name, ACL_TYPE_DEFAULT, acl)
     have the same effect as
                   acl_set_file (name, ACL_TYPE_EXTENDED, acl):
     Each of these calls sets the file's ACL.  */

  if (ctx->acl == NULL)
    {
      /* Remove ACLs if the file has ACLs.  */
      acl_t acl;
      if (HAVE_ACL_GET_FD && desc != -1)
        acl = acl_get_fd (desc);
      else
        acl = acl_get_file (name, ACL_TYPE_EXTENDED);
      if (acl)
        {
          acl_free (acl);

          acl = acl_init (0);
          if (acl)
            {
              if (HAVE_ACL_SET_FD && desc != -1)
                ret = acl_set_fd (desc, acl);
              else
                ret = acl_set_file (name, ACL_TYPE_EXTENDED, acl);
              acl_free (acl);
            }
          else
            ret = -1;
        }
    }
  else
    {
      if (HAVE_ACL_SET_FD && desc != -1)
        ret = acl_set_fd (desc, ctx->acl);
      else
        ret = acl_set_file (name, ACL_TYPE_EXTENDED, ctx->acl);
      if (ret != 0)
        {
          if (! acl_errno_valid (errno)
              && ! acl_extended_nontrivial (ctx->acl))
            ret = 0;
        }
    }
  *acls_set = true;

#  endif

# elif defined GETACL /* Solaris, Cygwin, not HP-UX */

  /* Solaris 2.5 through Solaris 10, Cygwin, and contemporaneous versions
     of Unixware.  The acl() call returns the access and default ACL both
     at once.  */

  /* If both ace_entries and entries are available, try SETACL before
     ACE_SETACL, because SETACL cannot fail with ENOTSUP whereas ACE_SETACL
     can.  */

  if (from_mode)
    return set_acls_from_mode (name, desc, ctx->mode, must_chmod);

  if (ret == 0 && ctx->count)
    {
      if (desc != -1)
        ret = facl (desc, SETACL, ctx->count, ctx->entries);
      else
        ret = acl (name, SETACL, ctx->count, ctx->entries);
      if (ret < 0)
        {
          if ((errno == ENOSYS || errno == EOPNOTSUPP || errno == EINVAL)
              && acl_nontrivial (ctx->count, ctx->entries) == 0)
            ret = 0;
        }
      else
        *acls_set = true;
    }

#  ifdef ACE_GETACL
  if (ret == 0 && ctx->ace_count)
    {
      if (desc != -1)
        ret = facl (desc, ACE_SETACL, ctx->ace_count, ctx->ace_entries);
      else
        ret = acl (name, ACE_SETACL, ctx->ace_count, ctx->ace_entries);
      if (ret < 0)
        {
          if ((errno == ENOSYS || errno == EINVAL || errno == ENOTSUP)
              && acl_ace_nontrivial (ctx->ace_count, ctx->ace_entries) == 0)
            ret = 0;
        }
      else
        *acls_set = true;
    }
#  endif

# elif HAVE_GETACL /* HP-UX */

  if (from_mode)
    ret = context_acl_from_mode (ctx, name, desc);

  if (ret == 0 && ctx->count > 0)
    {
      if (desc != -1)
        ret = fsetacl (desc, ctx->count, ctx->entries);
      else
        ret = setacl (name, ctx->count, ctx->entries);
      if (ret < 0)
        {
          if ((errno == ENOSYS || errno == EOPNOTSUPP || errno == ENOTSUP)
              && (from_mode || !acl_nontrivial (ctx->count, ctx->entries)))
            ret = 0;
        }
      else
        *acls_set = true;
    }

#  if HAVE_ACLV_H
  if (from_mode)
    ret = context_aclv_from_mode (ctx);

  if (ret == 0 && ctx->aclv_count > 0)
    {
      ret = acl ((char *) name, ACL_SET, ctx->aclv_count, ctx->aclv_entries);
      if (ret < 0)
        {
          if ((errno == ENOSYS || errno == EOPNOTSUPP || errno == EINVAL)
              && (from_mode || !aclv_nontrivial (ctx->aclv_count, ctx->aclv_entries)))
            ret = 0;
        }
      else
        *acls_set = true;
    }
#  endif

# elif HAVE_ACLX_GET && ACL_AIX_WIP /* AIX */

  /* TODO: Implement setting ACLs once get_permissions() reads them. */

  if (from_mode)
    ret = set_acls_from_mode (name, desc, mode, must_chmod);

# elif HAVE_STATACL /* older AIX */

  if (from_mode)
    ret = context_acl_from_mode (ctx);

  if (ret == 0 && ctx->have_u)
    {
      if (desc != -1)
        ret = fchacl (desc, &ctx->u.a, ctx->u.a.acl_len);
      else
        ret = chacl ((char *) name, &ctx->u.a, ctx->u.a.acl_len);
      if (ret < 0)
        {
          if (errno == ENOSYS && from_mode)
            ret = 0;
        }
      else
        *acls_set = true;
    }

# elif HAVE_ACLSORT /* NonStop Kernel */

  if (from_mode)
    ret = context_acl_from_mode (ctx);

  if (ret == 0 && ctx->count)
    {
      ret = acl ((char *) name, ACL_SET, ctx->count, ctx->entries);
      if (ret != 0)
        {
          if (!acl_nontrivial (ctx->count, ctx->entries))
            ret = 0;
        }
      else
        *acls_set = true;
    }

# else  /* No ACLs */

  /* Nothing to do. */

# endif

  return ret;
}
#endif

/* If DESC is a valid file descriptor use fchmod to change the
   file's mode to MODE on systems that have fchmod. On systems
   that don't have fchmod and if DESC is invalid, use chmod on
   NAME instead.
   Return 0 if successful.  Return -1 and set errno upon failure.  */

int
chmod_or_fchmod (const char *name, int desc, mode_t mode)
{
  if (HAVE_FCHMOD && desc != -1)
    return fchmod (desc, mode);
  else
    return chmod (name, mode);
}

/* Set the permissions in CTX on a file. If DESC is a valid file descriptor,
   use file descriptor operations, else use filename based operations on NAME.
   If access control lists are not available, fchmod the target file to the
   mode in CTX.  Also sets the non-permission bits of the destination file
   (S_ISUID, S_ISGID, S_ISVTX) to those from the mode in CTX if any are set.
   Return 0 if successful.  Return -1 and set errno upon failure.  */

int
set_permissions (struct permission_context *ctx, const char *name, int desc)
{
  _GL_UNUSED bool acls_set = false;
  bool early_chmod;
  bool must_chmod = false;

#if USE_ACL
# if HAVE_STATACL
  /* older AIX */
  /* There is no need to call chmod_or_fchmod, since the mode
     bits S_ISUID, S_ISGID, S_ISVTX are also stored in the ACL.  */

  early_chmod = false;
# else
  /* All other platforms */
  /* On Cygwin, it is necessary to call chmod before acl, because
     chmod can change the contents of the ACL (in ways that don't
     change the allowed accesses, but still visible).  */

  early_chmod = (! MODE_INSIDE_ACL || (ctx->mode & (S_ISUID | S_ISGID | S_ISVTX)));
# endif
#else
  /* No ACLs */

  early_chmod = true;
#endif

  if (early_chmod)
    {
      int ret = chmod_or_fchmod (name, desc, ctx->mode);
      if (ret != 0)
        return -1;
    }

  int ret = 0;
#if USE_ACL
  ret = set_acls (ctx, name, desc, false, &must_chmod, &acls_set);
  if (! acls_set)
    {
      int saved_errno = ret ? errno : 0;

      /* If we can't set an acl which we expect to be able to set, try setting
         the permissions to ctx->mode. Due to possible inherited permissions,
         we cannot simply chmod.  */

      ret = set_acls (ctx, name, desc, true, &must_chmod, &acls_set);
      if (! acls_set)
        must_chmod = true;

      if (saved_errno)
        {
          errno = saved_errno;
          ret = -1;
        }
    }
#endif

  if (must_chmod && ! early_chmod)
    {
      int saved_errno = ret ? errno : 0;

      ret = chmod_or_fchmod (name, desc, ctx->mode);

      if (saved_errno)
        {
          errno = saved_errno;
          ret = -1;
        }
    }

  return ret;
}